The musician said he had "a great time" working on the tracks in the studio in Manchester.

Writing on his blog, the Queen guitarist said: "As for unreleased material with Freddie singing ... strangely enough I was working on some tapes this evening - with William Orbit. There are a few items in progress. We will have something for folks to hear in a couple of months' time, hopefully."

Michael Jackson died in 2009. Credit: Reuters

He added: "Great evening with William Orbit working with some Queen/Freddie/Michael Jackson tapes. Exciting, challenging, emotionally taxing. But cool."

Freddie Mercury died in November 1991. Michael Jackson died 18 years later in 2009.